Efforts have been expended in determining a volume from an image. For instance, “Automatic Portion Estimation And Visual Refinement In Mobile Dietary Assessment”, Woo et al, Proceedings of the SPIE, Vol. 7533, (January 2010), discloses a technique for processing an image acquired by a RGB camera to estimate a volume of a food item captured in that image using camera calibration, image processing, volumetric modeling, and interactive user refinements to obtain that estimation. In another method disclosed in: “Measurement of Food Volume Based on Single 2-D Image without Conventional Camera Calibration”, by Y. Yue, W. Jia and M. Sun, 34th Annual Intl Conf. of IEEE EMBS, San Diego, Calif. USA, (August 2012), an image capture by a RGB camera is processed to estimate food volume. These approaches require the image to be acquired under tightly constrained conditions regarding the camera's position (or pose) relative to the food item or the use of a reference/calibration target with known physical dimensions, so that volume can be accurately estimated. Before this technology can be widely employed for general use, methods are needed for accurately estimating the pose of the camera used to acquire images of an object for which a volume is intended to be estimated.
Accordingly, what is needed in this art is a system and method for estimating a position (or pose) of a camera relative to a surface upon which an object rests in an image captured by that camera such that a volume can be estimated for that object.